Conventionally, as an interior material for vehicle, known is an interior material having a skin layer on an interior side of a base material layer, and having a backside layer on a vehicle body side of the base material layer.
For example, as shown in FIG. 19, an interior material 10 is formed by laminating a base material layer 11 in urethane, an interior side fiber layer 12 and a vehicle body side fiber layer 13 which are disposed so as to sandwich the base material layer 11, a skin layer 14 which is disposed on the surface of the interior side fiber layer 12 and forms a roof surface of the vehicle interior, and a backside layer 15 which is disposed on the backside of the vehicle body side fiber layer 13. Note that FIG. 19 shows a case where the backside layer 15 is placed at the top, and the skin layer 14 is placed at the bottom, corresponding to the direction of the interior material 10 to be mounted on the inside of a roof of a vehicle.
Among the above elements forming the interior material 10, the base material layer 11, the interior side fiber layer 12, the vehicle body side fiber layer 13 and the skin layer 14 are made of a breathable material generally. Therefore, by employing a non-breathable material for the backside layer 15, an air flow to the backside of the interior material 10 from the vehicle interior is stopped to prevent dust and the like from adhering to the surface of the skin layer 14.
The above described interior material 10 is manufactured by a manufacturing process as shown in FIG. 20. Note that FIG. 20 shows a case where the interior side skin layer 14 is placed at the top, and the vehicle body side backside layer 15 is placed at the bottom, corresponding to the direction of a molding material 10′ which is prepared for molding.
First, as shown in FIG. 20a, the molding material 10′ is prepared by laminating the base material layer 11, the vehicle interior side fiber layer 12, the vehicle body side fiber layer 13, the skin layer 14 and the backside layer 15. In advance, an adhesive 17 is applied over both the entire front and back surfaces of the vehicle interior side fiber layer 12 and the vehicle body side fiber layer 13 of the molding material 10′. Next, as shown in FIG. 20b, the molding material 10′ is sandwiched between an upper die 41 and a lower die 42 and is hot-pressed. Here, a back surface of the skin layer 14 is adhered to a surface of the vehicle interior side fiber layer 12, and a front surface of the backside layer 15 is adhered to a back surface of the vehicle body side fiber layer 13. Thus, an interior material 10 with a predetermined shape is obtained by integrating all the layers, as shown in FIG. 19.
By the way, conventionally, as an automotive interior material, for example, that disclosed in Japanese Patent Application Laid-Open Publication No. 2001-158306 (Patent Literature 1) is known. Japanese Patent Application Laid-Open Publication No. 2001-158306 (Patent Literature 1) discloses an automotive interior material comprising a substrate (corresponding to the base material layer) which is composed of a core material made of a resin foam and a surface mounting material (corresponding to the skin layer) laminated to the interior side of the core material, and an infrared ray reflection layer. The infrared reflective layer is attached towards a roof panel of an automotive body. It is disclosed that if the infrared reflective layer is formed with an aluminum deposition sheet for example, heat is shielded by the sheet even if sunlight incidents on the roof panel. The aluminum deposition sheet is described as a sheet in which aluminum is deposited on a substrate layer such as a plastic.
However, in the interior material 10 applied to a vehicle roof, the backside layer 15 made of a non-breathable material was formed with an aluminum deposition film. The aluminum deposition film functioned as an infrared reflective film, and thereby heat from the roof panel side was shielded. However, in an environmental test, it was found that there was disadvantage that the aluminum deposited on a base film tended to peel off from the base. It is considered that a cause of such a phenomenon is attributed to the reduction of the adhesion strength of the aluminum deposited on the base film to the base film that was promoted in the environmental test, due to entering of sebum into pinholes or cracks in the aluminum deposition film, which would be generated at points of contact with operator's hands during aluminum depositing operation.
Further, the automotive interior material of Japanese Patent Application Laid-Open Publication No. 2001-158306 (Patent Literature 1) includes a layer having an infrared reflecting function, facing the roof panel of the automotive body. The layer having an infrared reflecting function has a light reflectance of 50˜90% in a wavelength region of 350˜2500 nm, and a thickness is set to 0.1 μm˜1 mm. According to this, even if the heat from the sun may be transmitted on the automotive body, the heat is shielded by the layer having an infrared reflecting function. But this disclosure aims to reflect the infrared ray having the wavelength region of 350˜2500 nm. It is not a technique to reflect a far infrared ray. In addition, there is no description on the relationship between the configuration of the infrared reflective layer and the heat shielding effect in Japanese Patent Application Laid-Open Publication No. 2001-158306 (Patent Literature 1). Sufficient study on the optimal configuration of the infrared reflective layer effective for far infrared ray and a technique that maximizes heat shield performance of the infrared reflective layer are desired.
Furthermore, a technology is known where an interior material is applied to a sunshade of a sunroof made of a transparent member disposed in a vehicle roof. Such a structure is disclosed in Japanese Patent Application Laid-Open Publication No. 2010-208607 (Patent Literature 2), for example. Here, a sunshade is laminated from a plurality of base material layers made of an urethane foam each, a first glass fiber reinforcement layer adhere between the plurality of base material layers, a second and a third glass fiber reinforcement layers adhered to outer sides of the plurality of base material layers each, a skin layer adhered to outer side of the second glass fiber reinforcement layer, and a backside layer adhered to outer side of the third glass fiber reinforcement layer. In Japanese Patent Application Laid-Open Publication No. 2010-208607 (Patent Literature 2), a material laminated with a blackish nonwoven fabric is disposed as a skin layer of the sunshade. But, a temperature of the heat insulating smoked glass of the sunroof grows higher gradually by the radiant heat of the sunlight, and heat is accumulated in the nonwoven fabric skin material of the facing sunshade by the radiant heat from the heat insulating smoked glass. As a result, there is a problem that the temperature control efficiency decreases in the vehicle interior.